Move SUSv2 obsolete feature disabling to debug menu, invert meaning of
symbol (switched on to remove now: test your apps to make sure they _don't_
do this, because as some point we should just yank it), fixup head/tail/fold.

Also tweak "make allyesconfig" so anything starting with CONFIG_DEBUG gets
left switched off.  Possibly other things we want to put in the debug menu?
diff --git a/Makefile b/Makefile
index 9841659..09504e7 100644
--- a/Makefile
+++ b/Makefile
@@ -184,7 +184,7 @@
 
 allyesconfig: scripts/config/conf
 	@./scripts/config/conf -y $(CONFIG_CONFIG_IN)
-	sed -i -r -e "s/^(USING_CROSS_COMPILER|CONFIG_(DEBUG|STATIC|SELINUX|FEATURE_DEVFS|BUILD_AT_ONCE)).*/# \1 is not set/" .config
+	sed -i -r -e "s/^(USING_CROSS_COMPILER|CONFIG_(DEBUG.*|STATIC|SELINUX|FEATURE_DEVFS|BUILD_AT_ONCE))=.*/# \1 is not set/" .config
 	echo "CONFIG_FEATURE_SHARED_BUSYBOX=y" >> .config
 	@./scripts/config/conf -o $(CONFIG_CONFIG_IN)